The present invention relates to an input apparatus and a display apparatus that detect positional coordinates indicated and input the coordinates to an apparatus to be operated.
As an input interface for a personal computer apparatus to be operated) or the like, a coordinate input apparatus has been proposed that detects coordinates of an indicated position on an operation surface and inputs the coordinates to the apparatus to be operated. As such a coordinate input apparatus, there are known a touch panel that uses as an operation surface a display screen on which an image is displayed, a touch pad including a dedicated operation surface in addition to a display screen, and the like.
There is a projected capacitive technology as a principle of a coordinate detection in a coordinate input apparatus. In this technology, used is the fact that a capacitance in each crossing part of electrode wires provided in a matrix pattern on an operation surface varies due to the influence of an electrostatic bonding with an approaching operation object such as a user's finger and a stylus. Thus, the position of the operation object on the operation surface is detected. As a coordinate input apparatus that uses the projected capacitive technology, a “multi-point simultaneous input finger touch coordinate detection apparatus” is disclosed in Japanese Patent Application Laid-open No. H08-16307 (paragraph 0008, FIG. 1) (hereinafter, referred to as Patent Document 1).
In the detection apparatus disclosed in Patent Document 1, a plurality of X-direction electrode wires and a plurality of Y-direction electrode wires are provided in a matrix pattern, and an AC signal generator is connected to the X-direction electrode wires through a multiplexer, and a detector is connected to the Y-direction electrode wires through a multiplexer. When an AC signal is input to the X-direction electrode wires, the electrode wire cross capacitance is generated between the X-direction electrode wires and the crossing Y-direction electrode wires, thereby causing a current to flow through the Y-direction electrode wires. Then, the current is detected by the detector. The multiplexer connected to the X-direction electrode wires switches the X-direction electrode wires to which the AC signal is to be input, and the multiplexer connected to the Y-direction electrode wires switches the Y-direction electrode wires to be subjected to the detection, thereby switching the crossing part whose cross capacitance is measured.
When a user's finger is approaching the vicinity of a crossing part of the X-direction electrode wires and the Y-direction electrode wires, the electrode wire cross capacitance is reduced due to an electrostatic bonding between the user's finger and the X- and Y-direction electrode wires. In view of this, based on the output of the detector, the crossing part whose crossing capacitance is reduced, that is, the crossing part that the user's finger is approaching is specified, thereby detecting positional coordinates indicated.